We have evaluated the risk of sexual transmission of hepatitis C virus
(HCV) infection among 895 monogamous heterosexual partners of HCV chronically
infected individuals in a long-term prospective study.

Methods / Results

The follow up period was 8060 person-years; 776 (86.7%) spouses were
followed up for ten years. corresponding to 7760 person-years of observation
and 119(13.3%) spouses (69 whose infected partners cleared the virus following
treatment and 50 who ended their relationship or were lost at follow-
up) contributed for additional 300 person-years.

During the follow-up three HCV infections were observed corresponding
to an incidence rate of 0.37 per 1,000 person-years. However, in one case
the infecting HCV genotype in a spouse was different from that of the
partner ((2a, 1b), likely excluding a sexual route of transmission. Despite
the remaining two couples had concordant genotypes, sequence analysis
of the NS5b region of the HCV genome, coupled with a phylogenetic analysis
showed that the corresponding partners carried different viral isolates,
again excluding the possibility of intraspousal transmission of HCV.

Conclusion

These findings indicate an extremely low or even null risk of HCV transmission
within heterosexual monogamous couples.